The 350 years between the Han Dynasty and Sui Dynasty were a time of great turmoil including the disintegration of China from the 3rd to 7th centuries, the rise and fall of several kingdoms and dynasties, and the gradual reunification of China under the Sui Dynasty. The period is often referred to as the Six Dynasties period, as it saw the rise and fall of six major dynasties - Jin, Song, Qi, Liang, Chen, and Northern Wei - as well as numerous minor kingdoms and states. The political instability and fragmentation of the period was in part due to external pressures from nomadic tribes from the North and West, as well as internal power struggles and rebellions within China itself. Despite the chaos and warfare of the period, there were also significant cultural, intellectual, and artistic developments during this time, including the rise of Buddhism and the development of Chinese calligraphy and painting.